1. Field of the Invention
The present invention relates to an ink supply system and an image recording apparatus including the ink supply system which stably supplies the ink fed from an ink supply section to a plurality of ink nozzles in recording heads.
2. Description of the Related Art
In recent years, an image recording apparatus which easily, inexpensively and rapidly records an image on a recording medium has a recording head group (a linear ink head module) mounted therein. The recording head group has a structure in which a plurality of recoding heads are arranged in rows on a fixed carriage. An image recording apparatus which records an image with respect to a recording medium to be carried in this manner has been put into practical use.
In general, this recording head group is arranged to be greater than a width of a recording medium along a direction (a width direction of the recording medium) perpendicular to a carriage direction of the recording medium, and a plurality of ink nozzles arranged in each recording head along the width direction of the recording medium. The plurality of ink nozzles form a nozzle line. In the case of an image recording apparatus which performs color recording, a plurality of nozzle lines corresponding to this color recording must be configured.
In order to improve and stabilize a quality of an image to be recorded, a pressure loss of the recording head group with respect to an ink path must be uniformed when supplying the ink to respective recording heads for the same color.
As a prior art of a recording apparatus which uniforms such a pressure loss of an ink path, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2003-251826 is disclosed. FIG. 9 shows a recording apparatus disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-251826.
In this recording apparatus is provided a liquid storing container 72 (including a negative pressure stabilizing mechanism) having a movable member 71 which can at least partially transform in accordance with an amount of ink, a spring member 73 which exercises a spreading force with respect to the movable member 71 to generate a necessary negative pressure (a pressure loss), and communication openings 74 through which air is introduced into the inside in accordance with an increasing negative pressure.
This recording apparatus introduces air into the liquid storing container 72 from the communication openings 74 in accordance with an amount of ink in the liquid storing container 72. A negative pressure in the liquid storing container 72 is stabilized by the introduced air and the spring member 73. Therefore, a pressure loss of an ink path is uniformed. As a result, the recording apparatus stably supplies the ink.
Further, Published Japanese Patent No. 2738777 also discloses a similar inkjet recording apparatus. In this inkjet recording apparatus are provided each recording head provided in accordance with ink of each of a plurality of colors, an ink supply source which supplies the ink to each recording head, and each ink supply tube which couples each recording head with the ink supply source.
A length of the ink supply tube (an ink supply path) is configured to be shorter as the ink supply tube is compatible with ink which is apt to be hardened and fixed.